asd.py

import os
import sys
import signal
import asyncio
import contextlib


@contextlib.contextmanager
def parallel(processes):
    pids = []

    try:
        for _ in range(1, processes):
            pid = os.fork()
            if pid == 0:
                try:
                    yield None
                except SystemExit as e:
                    os._exit(e.code)
                except BaseException as e:
                    sys.excepthook(e.__class__, e, e.__traceback__)
                    os._exit(1)
                os._exit(0)
        yield

        for p in pids:
            os.waitpid(p, 0)
    finally:
        for p in pids:
            os.kill(p, signal.SIGKILL)
            os.waitpid(p)


class EchoProtocol (asyncio.Protocol):
    def connection_made(self, transport):
        print('new connection @', os.getpid(), self)
        self.transport = transport

    def connection_lost(self, exc):
        print('lost connection @', os.getpid(), self)

    def data_received(self, data):
        self.transport.write(data)


if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(loop.create_server(EchoProtocol, '', 12345))
    print('running on localhost:12345')
    with parallel(4):
        loop.run_forever()